Welcome to the forum!
A pain in head and neck area that aggravates with sneezing can be due to pinched nerves. This can happen due to overuse of computers, work involving straining of neck, canal stenosis, bone disease, spondylosis, poor posture etc. Use a hard bed to sleep. Avoid a pillow.
Roll a towel and place it under your neck while sleeping. Initially this will be uncomfortable but with time the acupressure will do wonders. Use an analgesic cream or spray. Anti-inflammatory drugs help. A good physiotherapist can teach you some exercises which will help you a lot. A MRI of the cervical spine may be required if these tips do not help. You would then need to consult a neurologist.
Hope this helps. Please let me know if there is any thing else and do keep me posted. Take care!